I had this problem a couple of years ago, I dragged the file to the desk top and erased it then the next file I deleted to the recycle bin registered correctly with Eraser. You could also try un installing Eraser deleting the heidi folder in the registry then re installing Eraser.
http://bbs.heidi.ie/viewtopic.php?f=35&t=5708. Eraser 6 shouldn't need this procedure however. This is because of the way Eraser follows Windows convention when erasing the recycle bin (erasing only files belonging to your current user account).